Rifling machine



y H. E. G. T. GERLICHI 2,003,185

RIFLING MACHINE s Sheets-Sheet 2 Filed Sept. 7, 1953 m N ME VENTOR I. ATTORNEY May 28; 1935 H. E. G; T. GERLICH RIFLINQ MACHINE Filed Se pt. '7, 1933 s Sheet s-Sheet 3 ATTORNEY Patented May as, 1935 sm'rs UNM'E' ZAIMJQE MAG Hermann Ernst Gustav Thorlsmund tl'ierllcli,

Bailey, Kent, England Application September 1933, Serial No. 63$,5b2

In Great Britain September 9, 1932 ll Claims.

5 bore of which is of constant, or substantially constant, diameter or width over part or parts of the length of the barrel, in front of the breech chamber, and tapered over another part of the barrel, said tapered part being long relative to said part or parts of constant diameter or width.

The present invention is especially applicable to the shaping of the internal surfaces, and more particularly to the riding part of the shaping, of barrels such as are described in my United States Patent No. 1,944,883 granted January 30th, 1934.

This patent describes a rifled barrel adapted to fire a flanged bullet the cross sectional area of the body of which is substantially equal to the cross sectional area of the barrel bore at the muz zle, the barrel bore being however at the breech end of the barrel of enlarged cross sectional area with regard to the muzzle. Actually oi course at the muzzle the bore is slightly greater in cross sectional area than the body or the bullet but a for the present purpose the two cross sectional areas may be regarded as being substantially the same.

Such a barrel bore has a groove bore which (ex cluding the breech chamber) is of constant enlarged cross section (with respect to the muzzle cross section) for a distance at the breech chamber end and may have a muzzle portion of constant cross sectional area at the muzzle end. The barrel bore also has a tapered portion between the muzzle-or muzzle rtion and said enlarged part of the barrel bore. The lands this barrel vary in height relative to the groove bore, and the lands bore varies in diameter and is of enlarged diameter at the end nearest the breech chamber of the barrel, such lands bore having in some cases more than one tapered portion, and having in'some cases one or more cylindrical portions as well as one or more tapered portions. In some cases the lands merge into the groove bore between the ends of the barrel,

the latter in such cases being only partially rifled.

The primary purpose of apparatus according to this inventionis the shaping of rifled barrels such as referred to above.

In barrels constructedagcording to my said Patent No'f1,944,883 the enlargement of the cross sectional area ol 'the bore at the breech end of the barrelmay be anything up to 200% or more of the cross sectional area at the muzzle of the barrel. e.

In order that the invention may be clearly understood and readily carried into practice, It haveappended hereto two sheets 01; drawings, il lustrating the same, wherein:

Figure l isa diagrammatic plan view of a boring apparatus constructed according to this invention, I

Figure 2 is a longitudinal sectional elevation showing diagrammatically the boring apparatus and the manner oi? using same,

Figure 3 is a detail view of the cutter box of ap paratus according to this invention,

Fill

Figure t is a cross smtion oi the same drawn to an enlarged scale, V

Figure 5 diagrammatic shows a method oi using the apparatusshown in Figures 1 to 4 Figure 6 is a diagrammatic plan view showing a rifling apparatus according to this invention,

Figure 7 shows a regulating arm for the same and for use when g with progressive twist is to be formed,

Figure 8 is a longitudinal sectional elevation showing diagrammatically the rig apparatus and method of using the same, a

Figure 9 is a perspective view of a clamping device for the apparatus, a

Figure 10 shows in cross section a boring l having four cutters,

Figure 11 shows in longitudinal section a modi= fled cutter box, P

Figures 12 and 13 show respectively modifies tions of the apparatus shown in Figures 1 and 6,

Figure 14 is a longitudinal sectional view or a part of a further modified cutter box, and

Figure 15 shows on a small scale one form 01. pattern rod constructed according to this inven .tion.

Figure 1 of the drawings shows boring apparatus for shaping the internal surface or a rifle barrel, I

In the diagram I is a rifle barrel shown mounted in clamping jaws 2 and 3 on a base 4 and is held against. rotation and axial movement by such jaws.

5 is a cutter box in the form of a long metal tube and this cutter box enters the barrel l and is less in diameter than the least internal diameter or the barrel. Where it enters the barrel the cutter, box is centred in the latter by a collar I mounted rotatably on ball bearings. Also the cutter box may be mounted in further bearings I.

The cutter box 5 is axially slldably mounted in To traverse the cutter box axially there is mounted adjustably thereon a screwed sleeve 9 passing through correspondingly screw threaded Jaws III which can be opened and closed by any suitable device.

Within the cutter -box is co-axially and axially slidably mounted a pattern rod I I rotatable in'a screwed sleeve I2 but axially movable with the latter. The sleeve I2 is adapted to be fed axially by means of a nut I3 having external'ratchet teeth engaged by a pawl I4 which may be opcrable by mechanical or manual means to traverse said pattern rod axially. The sleeve I2 is mounted on supports IS in which it is notrotat able.

Preferably the pattern rod 'II corresponds in shape or contour over a length corresponding to the part of the barrel to be machined, exactly with the internal shape it is desired to give this part of the barrel. The diameter of the pattern rod is ofcourse less than that of the barrel bore,

but the diameter of the pattern rod at any point is proportional to the diameter of the bore to be formed at the corresponding point.

As shown in Figure 2, diagrammatically and exaggeratedly, the cutter box 5 is provided with a pair of diametrically opposite radial slots l6, axially longer than they are wide (see Figure 3) and the axial length of said slots is disposed at an angle to the axis of the cutter box 5. When a cutter box is intended for rifling purposes said angle is substantially equalto the mean angle of the rifiing twist. It will be understood that in a barrel of varying diameter the angle of twist varies for a constant length of twist and it is the mean of the maximum and minimum angles of twist which is referred to.

In each of said radial slots I6 is mounted radially slidably a cutter I! having at its outer end a cutting blade l8 disposed transversely to the axial length of the cutter. The inner ends of the cutters are slightly curved at I9, such curve being struck from a point on the radial centre line (extended if necessary) of the cutter.

The cutters have close but sliding fits in the slots I6 and the cutters are pressed on to the pattern rod 5 by blade springs 20 attached to the cutter box and engaging in small holes (not shown) in the cutters, and the cutters are diametrically opposite and are adapted to operate in the same transverse plane and are each projected by the pattern rod an identical amount at all times during operation.

Figure 4 shows in cross section a barrel and the complete cutting apparatus, and from this figure it will be seen that the pattern rod I I may be of non-circular cross section and engage flats 2| on the cutter box so that the latter and the pattern rod rotate together. In this case the cutter operating surface of the pattern rod is on diametrically opposite parts but each of these parts is a replica in longitudinal contour of that part of the barrel bore the shape of which is determined by such pattern rod surface.

It will also be seen from this figure that the outer ends or the cutters Il may be reduced in width so that the blades I8 project slightly therebeyond so as to prevent accumulating of shavings or cuttings and detrimental effects resulting therefrom.

The above described apparatus may be used for boring a smooth bored barrel or a barrel to be rifled and can bore the barrel from end to end if the increase in bore diameter is not too great, but if this in rease is very large then the boring may be done in two or more portions.

By way of example there will be described the method of using the apparatus for boring a barrel which is to be rifled and the lands boreof which is to be of constant calibre for a distance ab (see Figure 2) from the muzzle of the barrel and is then to increase in calibre for a distance b-c and finally to remain of enlarged constant calibre for a further part of its length say c-d, and the groove bore of which barrel is to be of constant diameter from w-f, of increasing diameter from ,f-g, and of constant diameter from g--d (Figure 2).

Assuming the barrel has been cylindrically bored to a diameter substantially equal to the lands calibre at the muzzle of the barrel and that the barrel is to be shaped intwo overlapping operations a-i, and j-d, then the procedure is as follows:

The apparatus is arranged somewhat as shown in.Figure l, the cutter box being properly centred in the barrel; and the pattern rod being of a shape corresponding to that which the lands bore of the barrel is to be given, the various diameters of the pattern rod being throughout a constant amount-less than the diameter of the bore to be formed, and the pattern rod having a part 22 (which may be as long as the barrel) of constant diameter, a taperedpart 23, and a further enlarged part 24, of constant diameter (Figure 2).

At the start of the operation the cutters II are in their innermost positions and with their inner ends on the part 22 of the pattern rod and the cutter blades I8 lie just at the point d of the barrel, whilst the point K of the pattern rod lies also at the point 11 of the barrel. The cutter box is then traversed through the barrel by means of the sleeve 9 and parts associated therewith, the cutter box of course being rotated, the inner'ends of the cutters riding on the surface of the part 22 of the pattern rod.

The cutter box is then withdrawn from the barrel by first releasing the sleeve 9 from the jaws I0 and then drawing the cutter box axially in the direction of arrow 3 (Figure 1).

The pattern rod II is now fed forwardly into the barrel and cutter box by the screwed sleeve I2 and the associated mechanism. Now the cutter box is again passed through the barrel but this time at the commencement of the stroke the cutters are disposed on the tapered part 23 of the pattern rod I I and during the stroke slide down the part 23 on to the part 22. By this stroke an annular conical slice is cut from the barrel such as diagrammatically shown at 26 in Figure 5.

During the earlier operations when small conical ,after which the cutters may be changed for radially longer ones and the section i-d of the barrel may be shaped in a manner similar to that previously described, slices 21 being taken oil! in stages until the cutters finally define the contour t-u-m rv:c (Figures 2, 5 and 8). The cutters during the second stage of' operations are only traversed partially through the barrel namely up to the joint 7'.

The cutters usedfor shaping the portion 0-1 of the barrel are less in radial length than those which will be used for shaping part :i d of the barrel and in fact can only cut a surface of a diameter equal to the diameter at point i of the barrel.

For rifling the barrel shaped in the manner described the pattern rod in the cutting tool is replaced by another pattern rod corresponding in shape with the shape it is desired to give to the groove bore. This replacement is necessary unless the tapered portions of the groove and lands bores are of the same taper which is not a likely construction.

; of the cutters equals the smallest groove bore The apparatus for rifling is shown clearly and diagrammatically in Figure 6. In this apparatus the sleeve 9 shown in Figure l and its associated parts are dispensed with as is the driving device I. In this case the cutter box 5 passes non-axially slidably through a slide 28 mounted slid'ably on guides 29 on a bed 30. The cutter box 5 can rotate in the slide- 28. and on the cutter box is keyed a spur wheel II with which it must rotate. This wheel 3i gears with a slidable rack 32 mounted in bearings in the slide 28 and perpendicular to the cutter box 5. The end of rack 32 is guided by the walls of a slot 33 in an adjustable rifling twist regulating arm 34. This arm is adjustable relative to a scale 35 and can be locked in an adjusted position.

If the rifling is to be progressive then thearm 34 is suitably curved, as for example in Figure '7. q

The slide 28 may be reciprocated' parallel to the axis of the cutter box 5, to traverse the cutter through the barrel, by any suitable means.

The pattern rod is advanced as described with reference to Figure l.

To form the rifling grooves asfshown in Figure 8 (and as indicated in chain dotted lines in Figure 2) the barrel shaped internally as shown in full lines t.u.n.o.p.q.v. a:. Figure 2, is treated in a similar manner to that previously described for arriving at the lands bore shown in Figure 2, except that the cutter is,rotated under the action of rack 32 and that it is in this case desirable to provide the pattern rod as shownin Figure 8 with an elongation 10-11 of the conical part 23 of the pattern rod, 'or alternatively to form the front end of the pattern rod as shown in dotted lines in Figure 8 in which the pattern rod has an extra cylindrical part 38 whose diameter'plus the combined radial lengths of the-cutters equals the lands calibre at the muzzle ofthe barrel, the pattern rod having also a further conical part 31 the largest diameter of which plus the combined radial lengths diameter at the muzzle. This arrangement enables the grOOves to be cut in the constant muzzle part of the barrel. 1 a

This rifling may be done in two portions 0-! and g'-d. The first operation would cut the surface I'm'n'o'p'qr's'. The'second operation finishes the groove bore.

When it is desired to bore a cylindrical section of a barrel independently then the cutter apparatus can be used as an expanding boring rod ll would have to be freed from the sleeve l2 so that it could rotate and axially travelwith the cutter box. The pattern rod may ordinarily be secured to the sleeve l2 by a releasable set shown in Figure 10 in which also four radial cutters are shown, such cutters all being in the construction illustrated in the figure in the same circle.

when the pattern rod is made of circular cross section it may be a replica, on a smaller scale. of the bore it is required to give the barrel.

Such a device could have the clamp 40 shown in Figure 9 for use where necessary.

In Figure 11 is shown a cutter box having two pairs of cutters I], one pair being axially spaced from the other pair, the spacing of these cutters being determined as previously hereinbefore described.

Figure 11 also illustratesthe use of guiding pins 43 radially slidably mounted in the cutter box 5 and resting at the inner ends on the pattern rod II and at the outer ends following the bore of the barrel, these pins so serving to centre the pattern rod in the barrel. These pins preferably have rounded ends and in rifling a barrel may engage in the rifling to ensure that the cutters during their traverse exactly follow such rifling after the rifling has once been started.

The pins 43 may be pressed inwardly by springs 44 attached to the cutter box and engaging the pins.

The cutter blades used during boring operations preferably are disposed relative to the axis of the cutter box somewhat as shown in dotteddines x'a:' in Figure 3, whilst the blades for shown schematically by a member It so as to move together whilst the cutter box 5 is stationary in support 2. In this case the barrel is traversed by mounting it in sleeve 8 modified for the purpose and rotated by means 8 mounted on said sleeve.

Figure 13 shows asimilar arrangement adapted for rifling and having the parts 28, ll, 22, It and 3! associated therewith, these parts being similar to those shown in Figure 6 but are in this case operating the barrel instead of the cutter box. The cutting tools may operate in either direction of their travel through the barrel, that is either as they enter the barrel more deeply or as they are being withdrawn fromthe barrel.

Of course where the enlargement of the bore does notneed to be very large theboring or rifling may be done in one portion instead of in two or more portions.

Figure 14 shows an arrangement for rifling having pivotal hook-like cutters SI, 52 pivoted at It and 54 respectively at diametrically opposite points to the cutter box in slots therein and their ends whereby the cutting blades i8 at the free ends thereof have a magnified movement as compared with the parts enga ng the pattern rod and so the conicity of the pattern rod may in such casebe less than that ofthe suriaceto boeu't andsuchanarrangement isinmind wind the pattern rod I l acts on the cutters between it is said that the pattern rod is shaped correspondingly to the shape to which the barrel is to be cut.

Such a modified form as is shown in Figure 14 enables greater diameters to be rifled in one stage than is possible with the sliding cutters previously described and such cutters also are readily passed from a rifled part of one form to a rifled part of another form and gives accurate merging of these parts. Figure '15 shows one form of pattern rod for shaping the lands bore in a case wherethe lands bore is cylindrical for'a distance from the muzzle of the barrel, then gradually increases in diameter in a direction towards the breech chamber end of the barrel, then remains constant and enlarged for a distance, and then again increases gradually in calibre, as shown in dotted lines 10 Figures 2 and 8 in a direction towards the breech chamber.

Such a pattern rodhas cylindrical parts 60, 62, 64 and 66, joined by conical parts SI, 63, and 65. The parts 60, 62, 84 and 66 are each such that the sum of its diameter plus the length of the diametrically opposite cutters is for part 60 less than the lands bore at the muzzle; for part 62 equal to the finished lands bore at the muzzle; for part 64 equal to the finished lands here at the cylindrical enlarged section; and for part 66 equal to the maximum diameter of the lands bore. The parts 52, 63, 84, and 65 are the same in length as the corresponding parts of the finished lands bore.-

Obviously the shape of the pattern rod will depend upon the shape it is desired to give to the bore to be shaped.

Tapered parts 63 and 65 correspond in length and conicity with the tapered parts b-c and I0 Figure 2.

The part 65 may be dispensed with if the tapered lands bore part 10 is not required, or if this part of the lands bore is formed by a separate conical cutting tool as it may be. The part 66 of the pattern rod would then be of the same diameter as the part 64.

During a rifiing operation and. after each cutting stroke or after a certain number of cutting strokes the cutter box may be-rotated about its axis so that the cutters can cut a separate set of grooves. If two cutters are used and it is desired to produce four grooves then the rotation of the cutter box would be through 90 degrees. In all cases this rotation of thecutter box would depend on the number of cutters employed and the number of grooves required. If more than one set of cutters is used these sets would be axially spaced along the cutter box and the axial space between the sets, if two sets of two cutters were used each set cutting different grooves and both sets being arranged in the same plane, would be times the pitch of any one twist ,of the groove where x is any odd number.

' What I claim is:

1. Apparatus for shaping the internal surface of a barrel for a projectile propelling device and the bore of which barrel is to vary in its length in cross sectional area and comprising a rotatable cutting sleeve adapted to traverse the barrel to be shaped and having a plurality of circumferentially spaced radial slots, cutters each having a body part mounted slidably in one of said slots and having a single cutting blade at the outer part, a pattern rod mounted coaxially in said cutting sleeve and on which the inner parts of said cutters rest and adapted'to regulate .the radial setting of said cutters, the effective radial dimensions of said pattern rod varying in proportion to the varying radius of the surface to be shaped, said cutter body having its axial length disposed at an angle to the axis of the cutter box, the cutting blade of said cutter being disposed transversely to the body of the cutter, and the axis of the cutting sleeve, spring means adapted to retain said cutters in guiding engagement with said pattern rod, and said cutter bodies having curved surfaces engaging said pattern rod, means for traversing said cutting sleeve axially through the .barrel and relative to the barrel and the pattern rod, means for rotating the cutting sleeve, means for centering the cutting sleeve in the barrel, and means for mechanically advancing said pattern rod axially relative to the barrel.

2.Apparatus as claimed in claim 1 including guide pins mounted radially and slidably in said cutting sleeve and adapted at the inner end to ride on the surface of the pattern rod and at the outer end to engage the barrel.

3. Apparatus for shaping the internal surface of a barrel for a projectile propelling device and the bore of which barrel is to vary in its length in cross sectional area and comprising a rotatable cutting sleev adapted to traverse the barrel to be shaped and having a plurality of radial slots, cutters each having a body part mounted slidably in one of said slots and having a cutting blade at the outer part, said blade projecting at the ends beyond said body part, a pattern rod mounted coaxially in said cutting sleeve and on which the inner parts of said cutters rest and adapted to regulate the radial setting of said cutters, said pattern rod having an external surface the contour of which corresponds to the internal contour it is desired to give to the said barrel, spring means adapted to retain said cutters in guiding engagement with said pattern rod, said cutter bodies each having its axial length disposed at an angleto the axis of the cutting sleeve, the cutting blades of each of said cutters being disposed transversely to the body of the cutter, and said cutter bodies having curved surfaces engaging said pattern rod, means for traversing said cutting sleeve axially through the barrel and relative to the'barreland the pattern rod, means for rotating the cutting sleeve, mechanical means for advancing said pattern rod axially relative to the barrel in predetermined steps, said pattern rod having spaced cylindrical and co-axial parts of different widths joined by a single tapered part, the different parts of the patternrod merging into one another by smooth curved portions, and 'said pattern rod being rotatable with the cutting sleeve.

4. A device for shaping the internal surface of a barrel of a projectile propeling apparatus, the

bore of which'barrelis of considerably greater cross-sectional area at the breech chamber end than at the muzzle end and which gradually decreases from the portion of larger cross-sectional ing it through the barrel, a pattern rod co-axially disposed within 'the cutter sleeve, and said cutter blocks having rounded ends bearing on said pattern rod, spring means tending to force said outter blocks on to said pattern rod, the pattern rod leaving two spaced portions each of. substantially constant width-but of difierent widths to one another, these portions being joined directly together by a single tapered portion merging at its opposite ends directly into the said substantially constant width portions, means for centering the pattern-rod at one end of the barrel, means for advancing said pattern rod in predetermined steps relative-to the barrel and means for holding the pattern rod axially stationary relative to the cutter blocks during a cutting stroke of the latter, the longitudinal contour of said pattern rod corresponding with the longitudinal contour that it is desired to give to the barrel being operated upon.

5. A device for boring and rifllng the barrel of a projectile propelling apparatus, the bore of which barrel is of considerably greater cross-sectional area at the breech chamber end than at the muzzle end and which gradually decreases from the portionof larger cross-sectional area to the portion of smaller cross-sectional area by means of a tapered portion between the two portions and longer than either, comprising a boring sleeve provided with a pair of diametrically opposite radially adjustable cutters each having a single cutter blade transverse to the axis of the cutter sleeve and being itself transverse to such axis, means for rotating and axially traversing the cutter sleeve relative to the barrel, a pattern rod disposed co-axially within the cutter sleeve, means for mechanically advancing the pattern rod axially relative to the barrel in predetermined steps between cutting operations, means for maintaining the pattern rod stationary relative to the barrel during the cutting operation, said pattern rod having'two portions of. substantially constant width joined directly by a portion decreasing in width from the larger to the smaller of said substantially constant portions, said cutters each having its inner end bearing upon the surface of said pattern rodwhich is a replica of the surface to be produced in the barrel to be operated upon by the cutters.

6. A device according to claim 5 wherein spring means are provided adapted to force the said cutters onto the pattern rod.

'7. A device for boring and riliing the barrel of a projectile propelling apparatus, the bore of which barrel is of considerably greater crosssectional area at the breech chamber end than at the muzzle end and which gradually decreases from the portion of larger cross-sectional area to the portion of smaller cross-sectional area by means of a tapered portion between the two portions and longer than either, comprising a cutter sleeve, means for rotating and axially traversing said cutter .sleeve relative to the barrel, a plurality of radially adjustable cutter blocks each having a single cutting edge at its outer end, a pattern rod having two substantially constant portions of different widths joined together by a portion decreasing in width from one end to the other allin the same direction and longer than the constant width portions and having its larger end merging directly into the substantially constant width portion of greater width, whilst its other end merges directly into the constant portion of the smaller width, mechanical means for traversing said pattern rod relative to the barrel between cutting operations, means for maintaining the pattern rod axially stationary during cutting operations, said pattern rod having a longitudinal contour corresponding to that which it is desired to give to the inner surface of the barrel being operated upon, said cutter blocks bearing at their inner ends on said pattern rod, means for regulating the angle of twist of the rifling during the rifling operation, and guide pins radially-mounted in said cutter box and bearingv at the inner ends on said pattern rod and at the outer ends on the barrel.

8. A device according to claim '7 in which each cutter block has a single blade which projects at its ends beyond the cutter block by which it is carried.

9. A device according to claim '7 wherein the pattern rod has three axiallyspaced tapered coaxialportions of different maximum widths joined together by intermediate sections of different constant widths, the tapered sections all tapering in the same general direction.

10. Apparatus for shaping the internal surface of a barrel of a projectile propelling device, and the bore of which barrel is to vary in its length in cross-sectional area,,comprising a cutter sleeve, means for rotating and axially traversing said cutter sleeve within the barrel, a plurality of cutter blocks disposed in radial slots in said cutter sleeve, and each pivotally attached at one end to the cutter sleeve and having a single cutting edge at its opposite extremity only, a pattern rod disposed co-axially within said cutter sleeve and comprising a pair of axially spaced 'portions of substantially constant width joined together by a single tapered portion, and on the surface of which pattern rod the cutter blocks engage at a position between their ends, an antifriction bearing centeringisaid pattern rod within said barrel, means for mechanically axially advancing said pattern rod relative to the barrel between cutting operations, means for maintaining the pattern rod stationary relative to the barrel during cutting operations, and said pattern rod corresponding in longitudinal contour with the longitudinal contour it is desired to give to the surface to be cut in the barrel.

11. Apparatus according to claim 10 including means for varying the speed of rotation of ,the cutter sleeve relative to the barrel a rifling operation to give a progressive riflmg twist.

HERMANN ERNST GUSTAV I THORISMUND GERLICH. 

